1. Field of the Invention
The present invention relates to light transmissive optical devices and method, and has particular utility in the medical devices field as a laser catheter which can be percutaneously inserted into a cavity in the human body such as the esophogus, lungs and digestive system.
2. Description of the Prior Art
The prior art teaches a number of flexible, optically transmissive catheter arrangements for insertion into the human body. See for example the following U.S. Pat. Nos.: 4,175,545 to Termanini; 3,821,510 to Muncheryan; 3,866,599 to Johnson; 4,445,892 to Hussein et al.; 4,207,874 to Choy; 4,418,688 to Loeb; and 4,592,353 to Daikuzono.
Nonpatent literature references discussing the use of flexible laser catheters is also set forth in the following articles: "Laser Coronary Angioplasty: Experience with 9 Cadaver Hearts" by Daniel S. J. Choy, et al, The American Journal of Cardiology, Vol. 50, December 1982; "Transluminal Laser Catheter Angioplasty" by Daniel S. J. Choy, et al, The American Journal of Cardiology, Vol. 50, December 1982; "Effects of Carbon Dioxide, Nd-YAG," and Argon Laser Radiation on Coronary Atheromotous Plaques by George S. Abela, et al, The American Journal of Cardiology, Vol. 50, December 1982; "Laser Irradiation of Human Atherosclerotic Obstructive Disease: Simultaneous Visualization and Vaporization Achieved by a dual Fiberoptic Catheter" by Garrett Lee, et al, American Heart Journal, January, 1983; "Effects of Laser Irradiation on Human Thrombus: Demonstration of a Linear Disssolution-Dose Relation Between Clot Length and Energy Density" by Garrett Lee, et al, The American Journal of Cardiology, Vol. 52, October 1983; "Vaporization of Human Thrombus by Laser Treatment" by Garrett Lee, et al, American Heart Journal, August 1982; "Possible Laser Vaporization of Arterial Wall Lesions Set", Cardiology Times, October 1983; "Arterial Response to Laser Operation for Removal of Artherosclerotice Plaques" by Ross G. Gerrity, et al, The Journal, Thoracic and Cardiovascular Surgery, Vol. 85, No. 3, March 1983; and "Laser Angioplasty: Effects on Coronary Artery Stenosis" by H. Geschwind, et al, The Lancet, Nov. 12, 1983.
There have been commercially available fiber optic rod catheters employing a distal nozzle fixture for holding the distal end of the fiber optic rod at the extremity of the catheter. Such a device has been manufactured by Molectron Corporation of Sunnyvale, California and consists of an elongated metal spacer into which the fiber optic rod extends and which is threaded inside the sheath. The spacer includes longitudinal flutes along the outside of the spacer for permitting cooling fluids to pass. Another such commercial device has been manufactured by Cooper Lasersonics and MBB (a German medical device manufacturing consortium). As understood, that arrangement is also an elongated metal spacer into which the fiber optic rod is threaded, with longitudinal flutes permitting passage of a cooling fluid, and with an outside hose barb permitting interconnection with the outermost catheter sheath.